FOOD

Painted Buntings primarily feed on seeds, especially of grasses. Small invertebrates (primarily insects, but also spiders and snails) also are eaten regularly, at least during breeding, and are the sole diet of nestlings.

BEHAVIOR

Foraging
Painted Buntings most often forage on the ground; during the breeding season, however, buntings also may ascend as high as 10 m (33 ft) above the ground. Also, at coastal sites, buntings have been observed foraging in marshes as far as 50 m (164 ft) from forest cover. When foraging for seeds, buntings drag a seed-laden stem to the ground by fluttering up and grasp the stem with the bill; the bunting then strips the seeds while the stem is held against the ground with a foot. When foraging for arthropods, Painted Buntings sometimes eats extract and consume items from spider webs.

Singing
Male Painted Buntings sing as soon as they arrive on breeding territories. Males typically sing from an exposed, elevated perch (1-10 m [3.3-33 ft] above the ground); but the song also may be given from a perch more concealed among vegetation, especially by males on territory before the arrival of females, and by non-territorial males. The rate of singing may be as great as 10 songs per minute, during interactions between adjacent males during territorial establishment. The rate of singing declines markedly following the arrival of females, and shows yet another significant decline after pairs are established.

Singing by males on the wintering grounds has not been reported.

TERRITORIALITY

Reported territory sizes for breeding Painted Buntings range from 0.64 to 6.66 ha (1.58 to 16.46 acres). Sizes typically are larger for isolated territories, and smaller for territories that are contiguous with other territories; territories also are smaller and at higher densities in preferred habitats. High levels of year-to-year site fidelity have been reported in one study.

Male Painted Buntings vigorously defend territories by chasing intruding males, and with male to male fights. Bird-trappers capitalize on the strong territorial response of Painted Buntings by using a captive male as a decoy to lure birds into traps, a practice that was described as long ago as the early 19^th century.

Territoriality wanes after breeding, and buntings may congregate at food sources by August. On the wintering grounds, Painted Buntings may be found singly or in small flocks.

REPRODUCTION

Painted Buntings primarily are monogamous, but may be polygynous; rates of polygyny of up to 25% of a population have been observed. Females also may solicit extra-pair copulations, although there are few data on the prevalence of this behavior.

Painted Buntings often raise two broods within a single season, with an interval of 29-30 days between the fledging dates of the two broods.

Most males delay breeding until the third calendar year (just after attaining the brightly-colored, definitive male plumge), but some second-year males (i.e., males in a plumage that still is mostly green) establish territories and breed. Females begin breeding in the second calendar year.

Nest Type

The nest, which is built solely by the female, is a well-formed cup made of plant fibers, leaves, and other plant materials, with a lining of hair and fine grasses. The nest is firmly attached to vegetation. Nests usually are placed in low vegetation, 1-2 m (3.2-6.5 ft) above the ground; but may be high as 15 m (50 ft) above the ground, where suitable lower sites are not present.

Painted Bunting eggs are ovate, with a slightly glossy texture. The background color is grayish white or very pale bluish white; the eggs are speckled and spotted with various shades of brown and gray, the markings concentrated around the larger end of the egg. The dimensions of the eggs are 19 x 14.5 mm (0.75 x 0.57 in).

Clutch Size

Painted Bunting clutches usually are three or four eggs, although reported clutch sizes vary from one to five. Clutch size does not vary with latitude or with longitude. The only apparent geographic variation in clutch size is that mean clutch size decreases during the breeding season in the western population (from a mean of over 4 eggs/clutch in late March to a mean of less than 3.5 eggs/clutch by late August); no such decrease is reported for the eastern population.

Incubation
The incubation period is 11-12 days (mean 11.4 days). Only female Painted Buntings incubate the eggs.

Fledging

Hatchling Painted Buntings are altricial and nidicolous. They gain size at a rate of about 1 g/day. Nestlings have an insectivorous diet, and are fed entirely by the female. Fledging occurs after 8 or 9 days, at a weight of 10 or 11 g. Males will feed the fledged young if the female renests, and may remain together for up to 34 days. Juvenile Painted Buntings begin to form flocks, after becoming independent of parental care.

Brood parasitism

Painted Bunting nests are parasitized by both Brown-headed and (much less commonly) Bronzed cowbirds. The breeding range of the western population of Painted Bunting overlaps, in part, the historic range of Brown-headed Cowbird. Rates of nest parasitism by Brown-headed Cowbirds in the western population increased, at statistically significant levels, between the 1870s and 1980s. There are few reports of nest parasitism on the eastern population, which was allopatric to cowbirds until recently. Painted Buntings, at least in the western population, usually abandon the nest if it is parasitized early in egg-laying, but will accept cowbird eggs if the nest already contains more than three bunting eggs.

Life Span
In captivity, Painted Buntings have lived for up to 17 years 7 months. The oldest age reported for a free-ranging bunting is 12 years.